This disclosure generally relates to devices, systems, and methods for the remediation of NOx emissions generated from internal combustion engines. More specifically, this disclosure relates to ammonia generating devices for use in NOx abatement applications.
It is well known that internal combustion engines produce undesirable by-products as a consequence of burning hydrocarbon fuels (e.g. gasoline, diesel fuel, and the like) such as; carbon monoxide (CO), carbon dioxide (CO2), unburned hydrocarbons (HC) and nitrogen oxides (NOx). As regulations governing the emission of these by-products become increasingly more stringent, developing NOx abatement systems to achieve these mandates are of great importance. Although significant advancements have been achieved in reducing CO and HC emissions, further developments are needed to decrease NOx emissions.
Selective catalytic reduction catalysts (SCR's), for example, have shown promise at achieving this goal. These devices are capable of storing ammonia (NH3) for the subsequent reduction of nitrogen oxides (NOx) into hydrogen (H2) and water (H2O). These devices have proven to be exceptionally efficient at reducing NOx, however carrying liquid ammonia for injection into the exhaust stream is cumbersome and costly. As a result, the development of “on-board” generation of ammonia has become imperative to the success of these devices and their benefits of reducing NOx emissions.
An ammonia generator is disclosed herein that utilizes a catalytic substrate to react a reformate produced by an off-line fuel reformer with the exhaust stream of an internal combustion engine to produce ammonia. Furthermore, a NOx abatement system employing this ammonia generator has been designed which maximizes system efficiency.